Certain fasteners are designed for use with a corresponding purpose-built (as opposed to general-purpose) tool. For example, hex head fasteners (e.g., hex head bolts, hex nuts, hex head screws, hose clamps with hex head worm drives) may have a hexagonally shaped head that mates with a wrench having a corresponding size and shape. However, other fasteners are commonly tightened or loosened without tools or without purpose-built tools. For example, a fastener may have a head designed for gripping by hand or between a user's thumb and forefinger (e.g., a wing nut, a thumb screw, a hose clamp with thumb screw worm drive), referred to herein as “hand-tightened fasteners”. Heads of hand-tightened fasteners are generally designed to provide adequate torque while maintaining user comfort. For example, the head of a hand-tightened fastener may be relatively broad and flat or knurled.
Although hand-tightened fasteners may be tightened at least partially by hand, some may also need to be tightened using general-purpose tools (such as pliers). For example, in a particular application, a hand-tightened fastener may be specified to be hand-tightened and then further tightened a specified number of turns. When the hand-tightened fastener is in a hard to reach area or is visually obscured, it may be difficult for the user to apply a general-purpose tool (e.g., pliers) to perform the further tightening due, for example, to work space constraints or difficulty with mating the general-purpose tool to a head of the hand-tightened fastener. Moreover, additional effort by the operator may be required to maintain the grip of the general-purpose tool, such as pliers, on the fastener, possibly resulting in operator fatigue and/or inadequate tightening or the inability to loosen the fastener.